This invention is directed to solvents for cleaning, rinsing, and drying, which are binary azeotropes or azeotrope-like compositions containing a volatile methyl siloxane (VMS).
The value of volatile methyl siloxanes as solvent has been enhanced because the Environmental Protection Agency (EPA) determined that VMS such as octamethylcyclotetrasiloxane (D.sub.4), decamethylcyclopentasiloxane (D.sub.5), dodecamethylcyclohexasiloxane (D.sub.6), hexamethyldisiloxane (MM), octamethyltrisiloxane (MDM), and decamethyltetrasiloxane (MDDM), are acceptable substitutes for trifluorotrichloroethane (CFC-113) and methylchloroform. EPA also exempted VMS as a volatile organic compound (VOC), and added them to a list of compounds in 40 CFR 51.100(s) excluded from the definition of VOC, because VMS compounds have negligible contribution to tropospheric ozone formation.
Volatile methyl siloxanes have an atmospheric lifetime of 10-30 days and do not contribute significantly to global warming. They have no potential to deplete stratospheric ozone due to short atmospheric lifetimes, so they do not rise and accumulate in the stratosphere. VMS (i) contain no chlorine or bromine atoms; (ii) do not attack the ozone layer; (iii) do not contribute to tropospheric ozone formation (Smog); and (iv) have minimum GLOBAL WARMING potential. VMS are hence unique in simultaneously possessing these attributes, and provide a positive solution to the problem of finding new replacement solvents.